A great many different designs for catheters, wires, tubes, sheath and other instruments are known from the field of interventional medicine. Typical catheter designs include an elongate tubular body, commonly formed of a polymer material, which is advanced into a patient's body for a variety of diagnostic and treatment purposes. In the case of percutaneously introduced catheters and the like, the elongate tubular body commonly has a longitudinally extending lumen by which the catheter can be tracked over a wire guide from an opening in the patient's skin into a body lumen of the patient such as a vein or artery. Catheters can be navigated through a patient's vasculature for a variety of different purposes, such as delivery of a therapeutic treatment agent, removal of undesired body tissue, and the treatment of injuries, damaged tissues and even congenital defects.
Clinicians can encounter a variety of challenges during catheter or other instrument navigation through the vasculature. Twists, turns and obstructions within a vein or artery can all present obstacles to navigating a treatment device to a desired location. With the ever decreasing size and sophistication of interventional devices to enable their navigation to smaller body lumens and sites more remote from a percutaneous entry point, the design, materials, and functional properties of interventional devices are of ever increasing importance.
Various materials which until relatively recently would have been considered exotic are now in routine use in the construction of catheters, wires and other interventional devices. So-called shape memory alloys are one example of materials having desirable and sometimes counterintuitive properties, and now commonly used. Such materials can enable devices such as wires, stents, snares and other tools to be adjusted from a very small, low profile state for introduction into a patient's body and navigation to a site of interest, to a deployed state for treating the patient. One known interventional device configured for navigation through body lumens is disclosed in commonly owned U.S. Pat. No. 8,070,693 to Ayala et al.